DISCUSSION: Myasthenia Gravis is characterized by weakness and fatigability of skeletal muscles, usually associated with Thyroid disease, Hodgkin’s Lymphoma & Thymic gland abnormalities, with 85% as Thymic hyperplasia while 15% are Thymic tumors. Thymic tumors are composed of Thymomas, Neuroendocrine tumors and Thymic carcinomas. For most physicians, behavior of Thymic carcinoma is often confused with Thymoma due to its heterogeneous histology and rarity. Kelly reported Thymic carcinomas account for less than 1% of Thymic tumors. Surgery is the treatment of choice. According to Kondo, patients with advanced Thymic carcinoma who underwent both total and subtotal resection alone had 5-year survival rate of 30-67%. A study by Chen, using concurrent chemoradiotherapy, 16 patients with unresectable Thymic carcinoma was treated with debulking and chemoradiation, 5-year survival rate was 67.7%. Our patient suffered from Thymic carcinoma but she also had Myasthenia Gravis. What then is the incidence of Thymic carcinoma presenting as Myasthenia Gravis? Liu reported, 7.9% of patients with Thymic carcinoma had Myasthenia Gravis. Kondo reported, 2.2 % of 186 patients with Thymic carcinoma having Myasthenia Gravis. We did a literature review of 6 other studies on Thymic carcinoma of 247 cases from 1974 to 2003; none were associated with Myasthenia Gravis.